Introduction

The first question people always ask is "why?".
Well, the first 3 pictures should explain how unsatisfactory the stock
setup was when I reached about 7" of lift. The control arm
angles were way too steep, the steering was way beyond its design limits,
and the ride and handling sucked....and I wanted to go bigger yet.
So what to do? I could have done a custom multi-link design or one
of the so-called "long arm" conversions....but that's a lot
of trial and error and geometry to make it all work well. So I chose
the simple, proven reliability and performance of the leaf spring over
axle setup. I just love the clean simplicity and the ease of fine
tuning the lift height and wheelbase.

Scary stock steering angles.

Gross
control arm angles, and these were already custom adjustable-length control
arms.

The ugly
truth behind the rubber boots.

I basically set about emulating the
simple YJ design, but spring over axle (SOA).

SOA has worked extremely well for the
short wheelbase guys for years.

And I had access to free YJ front springs
(thanks Chad!).

The next
few pics show the initial step of cutting off the XJ coil bracketry.

This was my first time with the ol'
flame wrench (thanks to Rico for hauling his out here for me).

I made an ugly job of it, but as Chad
keeps saying..."you're not building a space shuttle) :-)

Because of the required location (to
centre the axle) for the driver's spring perch, the diff housing requires
some modification.

The inner U-bolt on the driver's side
needs to fit around the stub on the diff housing.

All the coil brackets removed.

The inner U-bolt on the passenger side
fits around the large disconnect housing, which needs a little "cleaning
up". If you're working with a non-disconnect housing, this won't
be an issue Personally I like the strength of the big cast disco housing.

Driver's spring perch mock-up.

Passenger side spring perch mock-up.

The
required placement of the spring perches requires 2 different
diameters. Good job I was making them myself.

3 different size U-bolts were required,
as follows:

2.5" - Passenger and Driver side outer

3" - Passenger inner (to fit around disco housing)

3.25" - Drivers inner, to fit around diff housing

U-bolt plates are just 1/4" steel plate.

This is how the perches will sit to
centre the axle under the Jeep. To figure out the locations, here's
what I did. Mounted the rear of the leaf packs in the stock LCA frame
brackets. Measured diagonally between them to get them parallel to
one another and the frame. With them in this orientation, measured
the width between the centring pins of the leaf packs (dimension A).
I then measured the width of the axle from inner knuckle to inner knuckle
(dimension B). Subtract A from B, result is C. Divide C by 2,
result is D. Measure from inner knuckle (same location as used in
getting dimension B) in an amount equal to D. This is where the centre
of the new spring perch needs to be.

Initial mock-up of leaf spring location.

This is how I measured between the
centre pins of the spring packs.

Showing where front will mount.
I did not want to do a shackle reversal because I didn't want to buy a new
"high travel" front drive shaft, and according to my research,
it would be of little or no benefit, and could even be counter-productive.
Check out John Nutter's excellent article on the subject at www.jeepwire.com.

I was
fortunate enough to have a big sturdy custom bumper of 1/4" plate to
mount my shackle hangers to. It would be very simple to make a cross
member though.

My bumper attaches with many bolts.

I chose
to mount the rear of the leaf packs in the stock LCA frame brackets.
they were already there, in the right place, and the right width for the
spring eye bushings.

Like the
pic says, I drilled a new hole in the LCA bracket, 1.5" behind the
stock hole, so the wheelbase would come out stock.

Here's the axle installed for the first
time.

Pic with
many labels :-)

This pic shows how I accomplished moving
the axle back 5" (from where it would have been if I'd made no adjustments)
so the wheelbase would remain stock. Later, I would end up re-using
the centred spring perch hole, as opposed to the offset one I drilled, moving
the axle forward about 1.75" to keep my 36" Swampers off the back
of the front fender wells.

Note the inner knuckles are swapped on CJ units as part of my hybrid
axle with manual hubs project - detailed elsewhere on my site.

Here you
can see 2 initial concerns I had:

1) I placed the front shackle hangers a bit too far forward, leaving
the shackles almost vertical, where I would have preferred a steeper angle
to the shackle (bottom of shackle further forward than top) so there's no
chance it would fold back on itself against the frame and bend the
spring. This has turned out not to be a problem at all.

2) I was concerned about the stress of the short AAL on the spring
pack. In the end, I fine tuned the leaf pack by removing the
shortest stock lower leaf, and adding 2 long leafs, one almost full
length. The short AAL is also still present (1 year later) and isn't
a problem. I love how easy it is to fine-tune a leaf spring
suspension.

I did use the passenger side UCA axle
bracket and bushing as a track bar mount initially, but have since removed
the track bar and sway bar and am perfectly happy with the results.
My shocks are RS9000 set on stiffest setting on the street.

Despite
my concern (when I labelled the pic) the shackle position has been fine,
and the leafs have been customized to where they are equal and even.

I think I was a little too hard on
myself when I did up these pictures initially. It has all worked out
exceptionally well.

I
think...

...Leaf springs...

...Rock!!

Conclusion

If you're going to do this yourself, you will have to work out the steering on your own. As I customized my axle (D44 outers) at the same time, I used D44 flat top knuckles and built a custom Hy Steer crossover steering while I was at it. Articles are on my site elsewhere. If you're keeping the stock knuckles, you will have to work it out yourself. I imagine there may be problems with the drag link hitting the passenger leaf pack. Good luck !